Form submits to `data:,` on Chrome V55 after first submit when including HTML with JavaScript

[gburghardt]

In Google Chrome (version 55, Windows 7 Pro) the action attribute of the <form> tag changes from / to data:, if you include HTML and JavaScript in the code snippet, and after the first time you submit the form.

Steps:

1. Go to http://hilite.me

2. Enter the following code in the snippet editor:

   <button type="button" data-action="remove">Remove Phone</button>
   

3. Click the "Highlight" button

4. Open the developer console and inspect the <form> tag

5. The action attribute is now data:, instead of /

This causes the page URL to change to "data:," in the browser when clicking the "Highlight" button again.

In Firefox and Internet Explorer, the action attribute remains /.